Media Matters chief David Brock paid a former domestic partner $850,000 after being threatened with damaging information involving the organization’s donors and the IRS – a deal that Brock later characterized as a blackmail payment, according to legal documents obtained by FoxNews.com.

In an acrimonious lawsuit settled at the end of last year, Brock accused William Grey of making repeated threats to expose him to the “scorn or ridicule of his employees, donors and the press in demanding money and property.” Brock claimed in legal papers that he sold a Rehoboth Beach, Del., home he once shared with Grey in order to meet Grey’s demands, which he called “blackmail” in the lawsuit.

Brock, 49, heads the non-profit Media Matters for America, which bills itself as a watchdog of the conservative media but has recently come under fire for allegedly coordinating with Democrats in what could be a violation of its tax-exempt status.

Brock’s bitter legal battle with Grey, who is described in a Sept. 14, 2010, police report obtained by FoxNews.com as his domestic partner of more than 10 years, began after Brock began dating Washington, D.C., restaurant impresario James Alefantis about five years ago. For the next three years, Brock and Grey traded angry accusations, which were documented in the police report and were the foundation of a pitched legal battle replete with charges of blackmail, theft and financial malfeasance.